From: Ben Widawsky Date: Wed, 24 Apr 2013 06:15:29 +0000 (-0700) Subject: drm/i915: Assert mutex_is_locked on context lookup X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=186507e9e8e89d5920305fdffd8cbba6366da795;p=linux-beck.git drm/i915: Assert mutex_is_locked on context lookup Because our context refcounting doesn't grab a ref at lookup time, it is unsafe to do so without the lock. NOTE: We don't have an easy way to put the assertion in the lookup function which is where this really belongs. Context switching is good enough because it actually asserts even more correctness by protecting the default_context. Signed-off-by: Ben Widawsky Reviewed-by: Jesse Barnes [danvet: s/BUG/WARN/] Signed-off-by: Daniel Vetter --- diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c index efa0ede5c679..c81ae52c8c2e 100644 --- a/drivers/gpu/drm/i915/i915_gem_context.c +++ b/drivers/gpu/drm/i915/i915_gem_context.c @@ -463,6 +463,8 @@ int i915_switch_context(struct intel_ring_buffer *ring, if (dev_priv->hw_contexts_disabled) return 0; + WARN_ON(!mutex_is_locked(&dev_priv->dev->struct_mutex)); + if (ring != &dev_priv->ring[RCS]) return 0;